Epigenetics and the germline

Epigenetic processes affect three stages of germline development, namely (1) specification and formation of primordial germ cells and their germline derivatives through lineage-specific epigenetic modifications, in the same manner as other embryonic lineages are formed, (2) a largely genome-wide erasure and re-establishment of germline-specific epigenetic modifications that only occurs in the embryonic primordial germ cell lineage, followed by re-establishment of sex-specific patterns during gametogenesis, and (3) differential epigenetic modifications to the mature male and female gamete genomes shortly after fertilisation. This review will detail current knowledge of these three processes both at the genome-wide level and at specific imprinted loci. The consequences of epigenetic perturbation are discussed and new in vitro models which may allow further understanding of a difficult developmental period to study, especially in the human, are highlighted.     

Revealing Photoluminescence Modulation from Layered Halide Perovskite Microcrystals upon Cyclic Compression

Halide perovskites show promise for high‐efficiency solar energy conversion and light‐emitting diode devices owing to their bandgap, which falls within the visible optical range. However, due to their rigidity, GPa pressures are necessary to control the complex interplay between their electronic and crystallographic structure. Layered perovskites are likely to be controlled using much lower pressures by exploiting the optical anisotropy of the embedded organic molecules in the structure. This work introduces layered perovskite microplatelets and demonstrates the extreme sensitivity of their emission to cyclic mechanical loading in the range of tens of MPa. A drastic change in their emission is observed in situ, from near‐white to an enhanced blue color. This process is reversible, as is evident from a hysteresis loop in the photoluminescence (PL) intensity of the microplatelets. A combination of experimental analysis and computational modelling shows that such behavior cannot be attributed to changes in the crystallographic structure of the flakes. Instead, it suggests that, thanks to their structural anisotropy, microplate alignment and reorientation are responsible for the observed PL modulation. The possibility to tune the optical emission of layered perovskite crystals via low pressures makes them highly interesting as active materials in applications where stress sensing or light modulation is desired.     

Artisanal and experimental Pecorino Siciliano cheese: microbial dynamics during manufacture assessed by culturing and PCR-DGGE analyses

Traditional artisanal Pecorino Siciliano (PS) cheeses, and two experimental PS cheeses were manufactured using either raw or pasteurised ewes' milk with the addition of starter cultures. The bacterial diversity and dynamics of the different cheese types were evaluated both by culturing and characterisation of isolates, and a culture-independent approach based on the 16S ribosomal RNA (rRNA) gene. Following cultivation, artisanal and experimental cheese types showed similar microbial counts, and isolates belonging to Lactococcus lactis, Streptococcus thermophilus, Enterococcus faecalis and Leuconostoc mesenteroides were identified by phenotypic characterisation and comparison of the restriction fragment length polymorphism (RFLP) of the 16S rRNA gene to that of reference species. The culture-independent fingerprinting technique PCR and denaturing gradient gel electrophoresis (DGGE) of V6 to V8 regions of the 16S rRNA gene of samples taken during artisanal PS cheese manufacture, from raw milk to the ripened cheese, indicated relevant shifts in the microbial community structure. The dominance of Streptococcus bovis and Lactococcus lactis species in the traditional artisanal PS was revealed by 16S rRNA gene sequencing. Comparison of DGGE profiles of samples from milk to ripened cheese, derived from artisanal procedure and the two experimental PS cheeses during production showed similar trends with the presence of intense bands in common. Nevertheless, the profiles of several artisanal cheeses from different farms appeared more diverse, and these additional species are probably responsible for the generally superior flavour and aroma development of traditional PS cheese.     

The application of cryo-SEM techniques to the study of the symbiotic association in the Azolla leaf cavity

The preparation of frozen-hydrated samples for scanning electron microscopy to observe symbionts in Azolla is described and compared to the conventional method of chemical fixation followed by critical-point drying. The frozen-hydrated specimens preserve the structure of the associating symbionts and the liquid phase in the Azollaleaf cavity. The leaf cavity structure and the endosymbionts in the frozen-hydrated specimens were intact and unharmed throughout the fixation. The cyanobiont cells were distributed along the envelope of the leaf cavity, and did not aggregate around the hair cells, as reported for chemical fixation specimens. The mucilage layer removed by the chemical fixation could be observed in the cryo-fixation specimens, especially at the lower part of the cavity.     

A WebGIS for the dissemination of information on historical landslides and floods in Umbria, Italy

A web site was designed to disseminate new information on historical landslides and floods in Umbria, central Italy. The historical information was compiled through a thorough review of existing catalogues of historical landslide and flood events, supplemented by an extensive search of local historical archives and chronicles, for the period before 1900. The new catalogue lists 1983 landslide events in the period from 1139 to 2001, and 1956 flood events in the period from 860 to 2001. In the considered period, in Umbria there were at least 1,531 sites affected one or more times by landslides, and at least 1,071 sites affected one or more times by inundations. The seasonal distribution of landslides and inundations was found different before and after 1900, most probably because of incompleteness of the historical record prior to 1900. WebGIS technology was used to disseminate the geographical and thematic information on historical landslides and floods in Umbria. The GIS-based web site is aimed at a diversified audience of experts and private citizens seeking information on geo-hydrological hazards in Umbria.

Nonionic surfactants. Regioselective synthesis of fatty acid esters of α- and β-glucopyranose

Lipophilic esters of saccharides belong to the family of nonionic surfactants widely employed in pharmaceutical and cosmetics formulations. A very simple method is presented whereby 6-O-esters of α- and β-glucose can be prepared and isolated. Good results have been obtained in the synthesis of 6-O-oleyl derivatives by simple acylation with appropriate oleyl chloride. The condensing agent bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOP-Cl) allows the preparations of the same esters with better regioselectivity but with yields strongly dependent on the aliphatic chain length of the carboxylic acids employed.     

Personal Digital Assistant in an orthopaedic wireless ward: the HandHealth project

Personal Digital Assistant devices are becoming a frequently used device for the bedside care of the patient. Ways of application are many, but limitations are also numerous. Input device and monitor resolution are limited by the device size. Moreover, the choice of specific programs and the amount of storable data are limited by the quantity of memory. During HandHealth project a system was developed using a different point of view. Personal Digital Assistant is only a means to access data and use functionalities that are stored in a remote server. Using that system patient ward note can be showed and collected on the handheld device but saved directly on the Hospital Information System. Medical images can be showed on the device display, but also transferred to a high-resolution monitor. Large amount of data can be dictated and translated by remote continuous speech recognition.     

Antibacterial property on Gram‐positive bacteria of polypyrrole‐coated fabrics

Antibacterial activity against Gram‐negative bacteria of polypyrrole‐coated fabrics has been demonstrated in the past. In this work, biocidal efficacy of polypyrrole has been evaluated against Gram‐positive bacteria on textiles with different polypyrrole loading. Excellent bacterial reduction (≥99%) was found on cotton fabrics containing more than ～9 wt % of polypyrrole. Polypyrrole loading can be greatly reduced in presence of silver. Silver‐containing fabrics used in this work alone does not guarantee a complete biocidal effect, but the addition of just 2 wt % of polypyrrole showed a bacteria reduction of 99%. Moreover, stability to different washing procedures of the antibacterial activity was evaluated. Fabrics were characterized by scanning electron microscopy, energy dispersive X‐ray analysis, and infrared spectroscopy. Stability of the coating was assessed by abrasion tests. PPy showed excellent fastness to abrasion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41670.     

A Second,Druggable Binding Site in UDP‐Galactopyranose Mutase from Mycobacterium tuberculosis?

UDP‐galactopyranose mutase (UGM), a key enzyme in the biosynthesis of mycobacterial cell walls, is a potential target for the treatment of tuberculosis. In this work, we investigate binding models of a non‐substrate‐like inhibitor, MS‐208, with M. tuberculosis UGM. Initial saturation transfer difference (STD) NMR experiments indicated a lack of direct competition between MS‐208 and the enzyme substrate, and subsequent kinetic assays showed mixed inhibition. We thus hypothesized that MS‐208 binds at an allosteric binding site (A‐site) instead of the enzyme active site (S‐site). A candidate A‐site was identified in a subsequent computational study, and the overall hypothesis was supported by ensuing mutagenesis studies of the A‐site. Further molecular dynamics studies led us to propose that MS‐208 inhibition occurs by preventing complete closure of an active site mobile loop that is necessary for productive substrate binding. The results suggest the presence of an A‐site with potential druggability, opening up new opportunities for the development of novel drug candidates against tuberculosis.